Bob Fratkin likens his hobby to a sickness and he carries the proof of his words right on him.

"Look," he says, producing a small plastic display case and pointing to an almost tiny oval button. "When you pay $2,000 for one item like this, it's a disease. There's no other word for it."

Fratkin, in normal life, is a stockbroker, but he is also national president of the 2,400-member American Political Items Collectors (APIC) and is said to have one of the best collections of Teddy Roosevelt political memorabilia in the country.

Yesterday, he was serving as auctioneer for APIC's Washington area fall meeting, where 30 members of the Washington chapter gathered to buy, sell or trade all manners of campaign keepsakes.

Fratkin's $2,000 button was not for sale.

"It's a 1924 Davis-Bryan jugate," he said his sentences racing as he warms to his subject. Jugate, he explained, refers to a button with a picture of two candidates on it, in this case Democratic presidential candidate John W. Davis of West Virginia and his running mate, Charles Bryan, brother of William Jennings Bryan.

Davis, it seems, was one of the great Constitutional lawyers in the history of the country. A strict constructionist, he argued more cases before the Supreme Court during the 20th Century than anyone else, was U.S. ambassador to Great Britain and at the age of 83 argued "the position of the Topeka, Kan., school board in the famous 1954 Brown vs. the Board of Education school Brown vs. the Board of Education school desegregation case.

"But he ran against Coolidge and lost," Fratkin said. "That's why nobody knows who is today, unless you collect buttons . . . and (getting) a John W. Davis is tough."

That's "what one little button can lead you to," Fratkin concludes.

Some of the organization's collectors took up the hobby after working in various political campaigns. Most, through, just seem to have a consuming interest in history and political science.

Yesterday's quarterly auction offered low-priced items from the campaigns of Richard Nixon, Dwight Eisenhower, John Kennedy, Gene McCarthy and Jimmy Carter as well as the ill-fated U.S. Senate race of Richard Obenshain, the Virginia Republican nominee who died recently in a plane crash while campaigning.

The auction was held in the cafeteria of The Washington Post at the invitation of two of its employees who are APIC members.

Collectors, who interests range from particular candidates or parties to broader groupings such as/third party candidates, banded together in 1973 to secure passage of the Hobby Protection Act restricting the reproduction of campaign material unless it is labeled as not authentic.

Carl Gordon, who works for Hahn Shoes, said he didn't start collecting buttons until 1976. "When I started, I didn't know anything. Now I know too much," he said, adding that he also has a house and basement full of buttons.

Sporting the most recent button "Ted-1980" congressional aide Rick Spear said he got the sure-to-be-collectors item from a Democratic official in New Hampshire.

Sen. Kennedy spoke recently before the State Democratic convention there and ". . . they (the buttons) just showed up," Spear said. CAPTION: Symbol, This Davis-Bryan jugate (2 candidates on a button) is worth $2,000. By Robin Tooker - for The Washington Post